﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

namespace System.Windows.Forms
{
    using System.ComponentModel;
    using System.Globalization;

    /// <summary>
    ///  TreeViewImageIndexConverter is a class that can be used to convert
    ///  image index values one data type to another.
    /// </summary>
    public class TreeViewImageIndexConverter : ImageIndexConverter
    {
        protected override bool IncludeNoneAsStandardValue
        {
            get
            {
                return false;
            }
        }

        /// <summary>
        ///  Converts the given value object to a 32-bit signed integer object.
        /// </summary>
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string strValue)
            {
                if (string.Compare(strValue, SR.toStringDefault, true, culture) == 0)
                {
                    return ImageList.Indexer.DefaultIndex;
                }
                else if (string.Compare(strValue, SR.toStringNone, true, culture) == 0)
                {
                    return ImageList.Indexer.NoneIndex;
                }
            }

            return base.ConvertFrom(context, culture, value);
        }

        /// <summary>
        ///  Converts the given object to another type.  The most common types to convert
        ///  are to and from a string object.  The default implementation will make a call
        ///  to ToString on the object if the object is valid and if the destination
        ///  type is string.  If this cannot convert to the destination type, this will
        ///  throw a NotSupportedException.
        /// </summary>
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType is null)
            {
                throw new ArgumentNullException(nameof(destinationType));
            }

            if (destinationType == typeof(string) && value is int index)
            {
                if (index == ImageList.Indexer.DefaultIndex)
                {
                    return SR.toStringDefault;
                }
                else if (index == ImageList.Indexer.NoneIndex)
                {
                    return SR.toStringNone;
                }
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }

        /// <summary>
        ///  Retrieves a collection containing a set of standard values
        ///  for the data type this validator is designed for.  This
        ///  will return null if the data type does not support a
        ///  standard set of values.
        /// </summary>
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        {
            if (context != null && context.Instance != null)
            {
                object instance = context.Instance;

                PropertyDescriptor imageListProp = ImageListUtils.GetImageListProperty(context.PropertyDescriptor, ref instance);

                while (instance != null && imageListProp is null)
                {
                    PropertyDescriptorCollection props = TypeDescriptor.GetProperties(instance);

                    foreach (PropertyDescriptor prop in props)
                    {
                        if (typeof(ImageList).IsAssignableFrom(prop.PropertyType))
                        {
                            imageListProp = prop;
                            break;
                        }
                    }

                    if (imageListProp is null)
                    {
                        // We didn't find the image list in this component.  See if the
                        // component has a "parent" property.  If so, walk the tree...
                        PropertyDescriptor parentProp = props[ParentImageListProperty];
                        if (parentProp != null)
                        {
                            instance = parentProp.GetValue(instance);
                        }
                        else
                        {
                            // Stick a fork in us, we're done.
                            instance = null;
                        }
                    }
                }

                if (imageListProp != null)
                {
                    ImageList imageList = (ImageList)imageListProp.GetValue(instance);

                    if (imageList != null)
                    {
                        // Create array to contain standard values
                        //
                        object[] values;
                        int nImages = imageList.Images.Count + 2;
                        values = new object[nImages];
                        values[nImages - 2] = ImageList.Indexer.DefaultIndex;
                        values[nImages - 1] = -2;

                        // Fill in the array
                        for (int i = 0; i < nImages - 2; i++)
                        {
                            values[i] = i;
                        }
                        return new StandardValuesCollection(values);
                    }
                }
            }

            return new StandardValuesCollection(new object[]
                                                {
                                                    ImageList.Indexer.DefaultIndex,
                                                    ImageList.Indexer.NoneIndex
                                                });
        }
    }
}
